Users of recreational and/or transportation apparatuses, e.g., bicycles (indoor and outdoor), skis, and snowboards, are often secured to their respective apparatus while also being able to reliably disengage therefrom. In the case of a bicycle, “clipless” pedals are utilized which include clip-in pedals secured to the bicycle and a cleat attached to the bottom of each of the cyclist's shoes. “Clipless” pedals allow for the bicyclist to removably secure their shoes (and feet) to the bicycle pedals. The clip-in pedals can be spring loaded and permit the user to insert the cleat, depress the spring-loaded portion of the pedal, and secure the cleat to top plates of the pedal. By being clipped in, the cyclist will have increased power transfer through the pedal stroke, increased efficiency, and better control, among other benefits. However, when a cyclist wishes to stop they must unclip their shoe from the pedal instead of simply taking their feet off of the pedals. Additionally, if the cyclist is in an accident they will want to be able to unclip from the pedals quickly and effortlessly. To unclip and release the cleat from the pedal, the cyclist will generally twist their heel outwards until the cleat is released from the pedal. This unclipping process can at times be difficult and the cleat can become stuck in the pedal. In the case of an accident, the failure of a cleat to disengage a pedal can increase the risk or severity of an injury. Accordingly, what is needed is a “clipless” pedal that is secure but can also be easily and reliably disengaged.
Modular permanent magnet workpiece chucks are known in the art. For example, U.S. Pat. No. 7,161,451, which is hereby incorporated by reference in its entirety, discloses a permanent magnet chuck for holding or lifting workpieces. This type of chuck can include two magnetic layers that are stacked over one another and encased in a housing. Each of the magnetic layers are made up of a series of soft magnet blocks that are positioned about a center and divided by permanent magnet plates. That is, each magnetic layer comprises alternating soft magnetic blocks and permanent magnet plates. The magnetic layers can be, for example, square or circular shaped. If square shaped, the magnetic layers can contain an even number of soft magnet blocks, for example, two or four, that are shaped as cubes or rectangular prisms. If circular shaped, the magnetic layers can contain an even number of soft magnet blocks, for example, two, four, six, etc., that are shaped as circular sector prisms, e.g., extruded pie slices. The permanent magnet plates have two major faces that are positioned adjacent the interposed soft magnetic blocks. The first major face has a north magnetic polarity and the second major face, which is opposite the first major face, has a south magnetic polarity. The permanent magnet plates are positioned between adjacent soft magnetic blocks extending generally from the center of the magnetic layer to the perimeter, and such that each soft magnetic block is adjacent either only north magnetic faces or south magnetic faces of the two bordering permanent magnet plates, but not a north magnetic face and a south magnetic face. The soft magnetic blocks that are adjacent north magnetic faces will have a north polarity while the soft magnetic blocks that are adjacent south magnetic faces will have a south polarity. As a result, the soft magnetic blocks alternate between north polarity blocks and south polarity blocks, e.g., a first block has a north polarity, a second subsequent block has a south polarity, a third subsequent block has a north polarity, and so on. One of the magnetic layers can be connected to an external lug-nut that allows for the magnetic layer to be rotated by a tool. e.g., a wrench.
Each of the magnetic layers are configured as described above, and are placed on top of one another. The first and second magnetic layers can be overlapped in two different positions, an unaligned position and an aligned position. In the unaligned position, the polarity of the soft magnetic blocks of the first and second magnetic layers that overlap each other are of opposite polarity, e.g., the north polarity soft magnetic blocks of the first layer overlay the south polarity soft magnetic blocks of the second layer, and the south polarity soft magnetic blocks of the first layer overlay the north polarity soft magnetic blocks of the second layer. In this unaligned position, the magnetic flux lines are close-circuited, which prevents the magnetic force from extending beyond the first and second magnetic layers. As such, this unaligned position is known as a magnetically inactive state since the permanent magnet chuck will not exert a significant magnetic force on an external workpiece made of a ferromagnetic material. In the aligned position, the polarity of the soft magnetic blocks of the first and second magnetic layers that overlap each other are of the same polarity, e.g., the north polarity soft magnetic blocks of the first layer overlay the north polarity soft magnetic blocks of the second layer, and the south polarity soft magnetic blocks of the first layer overlay the south polarity soft magnetic blocks of the second layer. In this aligned position, the magnetic circuits are incomplete and open, allowing magnetic force to extend beyond the first and second magnetic layers. As such, this aligned position is known as a magnetically active state since the permanent magnet chuck will exert a magnetic force on an external workpiece made of a ferromagnetic material and thus secure the external workpiece to the permanent magnet chuck.
The permanent magnet chuck can be switched between the active and inactive positions by rotating one of the magnetic layers with respect to the other magnetic layer by using a tool to rotate the external lug-nut so that the polarity of the soft magnetic blocks is either aligned or unaligned. The degree of rotation to switch between positions is determined by the number of soft magnetic blocks. If four soft magnetic blocks are used then the first magnetic layer will have to be rotated 90 (e.g., one quarter of a full circle) with respect to the second magnetic layer to switch between active and inactive positions. If six soft magnetic blocks are used then the first magnetic layer will have to be rotated 60 (e.g., one sixth of a full circle) with respect to the second magnetic layer to switch between active and inactive positions.
The permanent magnet chuck as described above and in U.S. Pat. No. 7,161,451 is known to be implemented with a work-holding device used in machining operations. e.g., for grinders, lathes, and mills, and for material handling purposes. For work-holding applications, the permanent magnet chuck would hold a material that is being worked on. e.g., a piece of metal that is being lathed. However, the permanent magnet chuck of the prior art is not directed to magnetically securing the device or tool that is used to activate the permanent magnet chuck.
The present disclosure addresses the foregoing drawback and others by providing magnetic engagement mechanisms for recreational and/or transportation apparatuses, and/or by providing same that can be activated and de-activated by a user's foot or other appendage and releasably secures the user's foot or other appendage to the apparatus so that it can be quickly and reliably connected and disconnected through rotational activation of two magnetic platters.